1. Field of the Invention
This invention relates to a method and apparatus for controlling an engine which prevents a phenomena wherein a mixture is diluted (hereinafter, called "leanness phenomena") by correcting a fuel supply quantity in acceleration time.
2. Discussion of Background
A conventional control of this kind is shown, for instance, in Japanese Examined Patent Publication No. 27491/1989, wherein a fuel injection quantity is increased during acceleration times.
In the conventional control, the increase of fuel is controlled in accordance with an acceleration state, wherein an increase of wasteful fuel is prevented by increasing only the fuel necessary for the acceleration, or by reducing the increase quantity of fuel in the acceleration time, inversely to an increase in the rotational number of the engine, whereby purification of exhaust gas and saving of fuel are performed.
In the conventional control, a corrected fuel quantity determined by an acceleration state and the rotation number, is injected at an injection timing which succeeds an acceleration initiation. Accordingly, a large amount of air is sucked in a time period from the acceleration initiation to the succeeding injection timing, which causes the leanness phenomena. Therefore, in the acceleration time, knocking is generated and much nitrogen oxides (NO.sub.x) contained in the exhaust gas is emitted, which contaminates the air.